1. Field of the Disclosure
Exemplary embodiments of the present disclosure relate to a liquid container and an image forming apparatus including the liquid container.
2. Description of the Related Art
Image forming apparatuses are used as printers, facsimile machines, copiers, plotters, or multi-functional peripherals having two or more of the foregoing capabilities. As one type of image forming apparatus employing a liquid-ejection recording method, an inkjet recording apparatus is known that uses a recording head formed with a liquid ejection head (liquid-droplet ejection head) for ejecting droplets of ink.
Such image forming apparatuses employing the liquid-ejection recording method eject droplets of ink or other liquid from the recording head onto a recording medium to form a desired image (hereinafter “image formation” is used as a synonym for “image recording” and “image printing”).
Such liquid-ejection-type image forming apparatuses fall into two main types: a serial-type image forming apparatus that forms an image by ejecting droplets from the recording head while moving the recording head in a main scan direction, and a line-head-type image forming apparatus that forms an image by ejecting droplets from a linear-shaped recording head held stationary in the image forming apparatus.
Such an image forming apparatus (hereinafter also simply “inkjet recording apparatus”) may include, for example, a sub tank (also referred to as buffer tank or head tank, serving as a second liquid container) mounted on a carriage together with a recording head. In the image forming apparatus, an ink cartridge (main tank, serving as a first liquid container) is detachably attached to the image forming apparatus to supply and replenish ink from the ink cartridge to the sub tank.
The second liquid container and the recording head may be shipped either filled with ink or empty. However, if the second liquid container and the recording head filled with ink are stored for a long time, ink components may adhere to an area near nozzles of the recording head, thereby causing faulty ejection.
Alternatively, in a case in which the second liquid container and the recording head are empty when shipped, during initial ink filling air bubbles present in chambers of the recording head may cause faulty ejection.
Hence, for example, JP-2000-094708-A proposes filling the second liquid container and the recording head with another liquid besides ink (e.g., filler liquid or induction liquid). Then, by suctioning and discharging such liquid from the nozzles of the recording head in initial ink filling, ink is supplied from the first liquid container to the second liquid container to replace such liquid with ink.
In this regard, if liquid supplied to the second liquid container includes bubbles and such bubbles are supplied to the recording head, faulty droplet ejection, e.g., misdirected ejection or ejection clogging, can occur. For this reason, it is preferable that the second liquid container be able to store and exhaust air.
However, for a conventional second liquid container, liquid supplied from a first liquid container is stored in a liquid storage area and supplied from the liquid storage area to a recording head through a liquid discharge passage. For such a configuration, increasing the size of an air storage area for reserving air may make it much more difficult to replace the filler liquid with ink in the second liquid container. In other words, if a large area for reserving air is allocated in the second liquid container, a slow-current and stagnant area my arise, thereby causing reduced efficiency of replacing filler liquid with ink. Consequently, the amount of waste ink may increase. Further, if a large area is allocated to store air in the liquid container, the size of the entire liquid container may increase, thereby increasing the size of a head unit including the recording head and the liquid container as an integrated unit, which is undesirable.
Alternatively, if the second liquid container includes an air release mechanism that opens the interior of the second liquid container to the atmosphere, the configuration of the second liquid container may get complicated.